-77 = n-4(3-3n)
First you need to distribute the -4
-77 = n-12+12n
then combine like terms
-77 = 13n-12
then switch sides (I dont know, this just makes it easier for me to see)
13n-12=-77
then add 12 to both sides to isolate the variable
13n-12+12=-77+12
13n=-65
Then divide both sides by 13
13n/13=-65/13
n=-5